Everything a query says is said about a layer definition: a plain object. Groups nest those objects and pass properties down to them. This page is the vocabulary: the kinds of layer that exist, what distinguishes them, and which property list applies to each. The exhaustive, generated list of properties lives in the API reference — this page is the map of it.

1. A layer definition

{
  name: "CSR:estados",      // which map(s) — the only property with no default
  title: "States",          // what the layer panel shows
  visibility: true,         // starts visible
  opacity: 0.8,
  group: "background",      // optional: a reserved slot, see §4
}

Two properties decide how everything else is read:

PropertyDecides
sourceWhere the pixels come from: the catalogue, a calculation, a file, a tile service
nameWhich map, or — for a calculated layer — which maps, comma-separated, in order

2. The kinds of layer

sourceWhat it isThe properties that matterProperty group in the API reference
(absent) or "local"One published map, drawn as WMS tilesstyles, extents, minscale / maxscale, startLegendOpen, hideStyleChooserLayersProperties, ConfigLayer
"calculate"Several maps read together; your expression produces a new map from their pixelsname (list), operation, expression, beforeCalc, legendColor, insideOpacity, categorical, maxZoom, otherNamesLayersProperties, ConfigLayer, LayersFunctions, LayerInternal
"file"Vector features from a file, an inline object or your own loader — with type choosing whichtype, url, json, loadData, styleMap, onClick, onHover, clusterFileLayer, VectorLayer
"xyz"A tile service addressed by z/x/yurl, nameXYZLayer
"osm", "google", "arcgisrest"A ready-made basemapname selects the variant (for example mapnik, SATELLITE)LayersProperties

A layer registered through addRemoteWMSServer behaves as a catalogue layer; the registration says where its server is and whether it needs a proxy.

Only calculated, file and tile (xyz) layers have a panel in the layer list: descriptionHtml (text and widgets), paramsButtonConfig (row buttons) and exclusiveGroupDetails are ignored on published maps, basemaps and servers added with addRemoteWMSServer, while startLegendOpen and hideStyleChooser work on published maps only. maxZoom set in the query is read only by calculated layers; a published map takes it from its catalogue entry.

2.1 type, for file layers

type chooses how a source: "file" layer obtains its features (case-insensitive):

typeSource of the features
loadYour loadData(inputs, config) callback loads them; it must announce the load with the layer’s startLoadingLayer / endLoadingLayer events
csvThe CSV at url, one feature per line
jsonThe inline json property: GeoJSON, or an array of plain objects
jsonurlJSON fetched from url (also the fallback for an unrecognised type)
geojsonurlGeoJSON fetched from url
emptyNo features; the query adds them later

A GeoJSON without a declared CRS is guessed from its first coordinate: EPSG:4326 when it looks like longitude/latitude, otherwise EPSG:3857. CSV and lists of plain objects use the query’s ExtjsUtils.CONFIGURATION.setOptions({ defaultFromProj }), then the link’s defaultFromProj, then the map projection. Declare crs in the GeoJSON, or fromProj on the layer, whenever the data is in anything else (UTM, for example) — a silent misalignment is the usual symptom.

2.2 operation, for calculated layers

A calculated layer’s name lists several maps; operation is a comma-separated list with one token per map, in the same order, saying how each map’s pixels are turned into the numbers expression receives. An empty token leaves that map on the default.

{
  source: "calculate",
  name: "CSR:pop_density_estimate_2015,CSR:estados,CSR:pop_density_estimate_2015",
  operation: "average,,area",   // map 1 averaged, map 2 default, map 3 as area
}
TokenThe value expression receives
(empty)The regular WMS image: the pixel’s legend colour/category
rawThe value of the most central original cell under the pixel
rgbaThe pixel’s RGBA bytes packed into one integer
sum / averageArea-weighted sum / mean of the cells under the pixel
max / minLargest / smallest cell at least partly under the pixel
integralSummed-area table: the sum over a rectangle from its four corners
areaintegralSummed-area table of the covered areas
areaOriginal map area inside the pixel
cellsWeighted count of original cells inside the pixel

Tokens are case- and whitespace-insensitive. Every token except the default and rgba requires the map to be published with that operation available; if it is not, the console reports Operation X is not defined for layer Y and the layer produces nothing.

3. Groups

Groups come in two kinds, and nest. A top-level group with title and elements becomes an entry of the top menu, which lists all its layers for the reader to turn on (GroupProperties.title). A group with viewTitle and elements becomes a heading in the layer panel, above the layers of it that are on:

[
  {
    viewTitle: "Boundaries",
    color: "#8b0000",
    openGroup: true,
    defaultProperties: { visibility: false, source: "local" },
    elements: [
      { title: "States", name: "CSR:estados", visibility: true },
      { title: "Municipalities", name: "CSR:municipios" },
    ],
  },
]
PropertyEffect
viewTitleThe group’s row in the layer panel; groups may nest by nesting elements
elementsThe layers, or further groups, inside it
defaultPropertiesApplied to every descendant that does not set the property itself
openGroupThe viewTitle heading starts expanded (also available per layer, where it expands the layer’s headings)
colorThe colour of the group’s viewTitle heading; on a top-level group, also of its top-menu entry and of the rows of all its layers. A color written on a layer is replaced by its groups’ colours
viewColorAccepted on a group, but it has no visible effect today
onClickViewGroup, onToggleViewGroupCalled when the group row is clicked or toggled, with this = the node. These need a real group: attached to a layer that is not inside a viewTitle, they never fire
globalDeclares query globals while this group is interpreted

Interpretation flattens all of this into an ordered list of layers, each remembering its group path. Order inside a group is declaration order unless priority reorders it (higher first).

4. Reserved and special slots

SlotMeaning
group: "background"The layer is a basemap: it goes under everything and joins the background picker instead of the layer list
group: "<any other value>"Ignored: only "background" is read. To let one of several layers be visible at a time, use toggleGroup
paramsButtonConfigExtra buttons on the layer’s row — query, download, tooltip and toggle buttons; a bare object is treated as one entry of type query. Calculated, file and tile layers only
descriptionHtmlThe layer’s panel content: free HTML plus the widget markup of the widget markup language. Calculated, file and tile layers only

5. Presentation properties, in one place

These do not change what the layer computes, only how it appears. All are documented individually in the API reference under LayersProperties and ConfigLayer. Unless noted, they apply to every kind of layer:

  • In the panel: title, startListed, hideListing, hideMetadata, hideLegendButton, showRemoveBtn, useLayerTooltip, customLayerClass, verticalMenu; startLegendOpen and hideStyleChooser (published maps only); description (file and tile layers only); thumbUrl (published maps and tile layers only); legendTitle (calculated layers only).
  • On the map: visibility, opacity; minscale, maxscale and hideTilePlaceholder (published maps and calculated layers); insideOpacity and maxZoom (calculated layers only). The map’s extent and attribution come from its catalogue entry, not from the query: limit the area with extents.
  • In the legend of a calculated layer: categorical, categoricalPalette, maxQntEntries, showLoadingModal (also on file layers).

6. How to find a property

Where to find it shows, for anything you want to change, where it is written (in a layer, in a group, before the layer list or in the map’s link) and which part of the API reference lists it. If a property appears in an old query and does nothing, check pitfalls and properties that do nothing before trusting it.

Generated API entries for this chapter

Every property and function named here is listed, with its type, default and example, in the generated API reference: